Cellulose-ether solvent and composition



Patented May 20, 19245 UNITED STATES PATENT OFFICE.

EDWARD S. FABROW, JR, KOCHESTER, NEW YORK, ASSIGNOR TO EASTMAN KODAK COMPANY, OF ROCHESTER, NEW YORK. A CORPORATION OF NEW YORK.

GmULOSE-ETHER SOLVENT AND COMPOSITION.

No Drawing. Application filed July 7,

To all whom it mmy concern:

Be it known that I, EDWARD S. FARROW, J r., a citizen of the United States of America, residing at Rochester, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Cellulose-Ether Solvents and Compositions, ofwhich the following is a full, clear, and exact specification.

This invention relates to solvents for making strong flowable solutions of cellulose ether and also relates to the cellulose ether compositions produced by the aid of such solvents. One object of the invention is to provide a solvent which will dissolve lar e proportions of cellulose ethers and at t e same time lated viscosity for use in plastic and in making arts. Another object of my invention is to provide a cellulose ether solution, which has a regulated viscosity for making strong, flexible, transparent film on the machines and b the methods known in the art.

In U'. S. atent No. 1,188,376, Lilienfeld,

June 20, 1916, there are disclosed a series of alkyl ethers of cellulose; Certain of these are practically insoluble in water, and my invention is particularly applicable to ethers having that property, although not so limited to them. Such others form stron and useful solutions in mixtures of methy acetate and methyl alcohol. Nevertheless it is sometimes desirable to reduce the viscosity of such solutions, in order to regulate as them for film manufacture, without sub.

stantially diluting them.

I have dimovered that such regulation of the viscosity may be effected by adding small amounts of benzoic acid to the mix- 4o ture of methyl acetate and methyl alcohol. Benzoic acid by itself does not have as much solvent action on cellulose ether as a mix ture of methyl alcohol and methyl acetate. The addition of small amounts of it to at such mixture would not, therefore, be expected to have a lowering efiect on the viscosity of the resulting solution of cel lulose ether. But an amount of benzoic acid equal to one-seventicth of the weight of co the methyl acetate and methyl alcohol mixture, for cxple, will lower the viscosity ield solutions having a re 1922. Serial No. 573,485.

of a thick solution of cellulose ether in such mixture by about 15 to 20 per cent. This sur rising action indicates that the benzoic aci has a strong latent solvent power which is made active under these circumstances.

The proportions may vary considerably, but I find that a solution containing 1 part by weight of benzoic acid to parts of the mixture of methyl acetate and methyl alcohol is particularly useful, yetsany dilution of the solution is negligible. The mixture of the acetate and alcohol may vary A also, but I prefer to use the ratio of parts by weight of the former to 10 parts by weight of the latter.

The amount of cellulose ether dissolved in the complete viscosity-regulating solvent may, of course, be considerably varied. By way of-example, I may dissolve 1 part of water-insoluble ethyl cellulose in from .3 to 6 parts of the mixed solvent.

It will be noted that some of the benzoic acid remains in the finished film formed by flowing or depositing such dopes in the usual way. Other substances which im art additional suppleness 0r incombustibi ity. or other qualities to the film may be added to the above solutions or dopes, such modifying agents being, for instance, triphenyl or tricresyl phosphate, camphor, monochlornapthalene, etc.

The ingredients are of the ordinary commercial type sufliciently purified for the process of film manufacture, so as to give dopes yielding films having the proper relative freedom from color.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A composition of matter comprising cellulose ether dissolved in a mixture 0 meghyl alcohol, methyl acetate and benzoic aci 2. A fiowable film-forming composition comprising an alkyl ether of cellulose dissolved in a mixture of methyl alcohol, methyl acetate and benzoic acid, the weight of the latter being approximately oneseventieth the combined weights of the methyl acetate and methyl alcohol.

3. A composition of matter comprising a solution of 1 part by weight of water-in- 5. As an article of manufacture, a flowed, soluble ethyl -cellulose in from 3 to 6 parts flexible, transparent film comprising waterof a mixture of methyl alcohol, methyl insoluble ethyl cellulose and benzoic acid. N acetate and bezoic acid. Signed at Rochester, New York, this 30th 5 4. As an article of manufacture, a flexiday of June, 1922.

ble film comprising cellulose ether and benzoio acid. I v EDWARD S. FARROW, JR. 

